Brakes (rear) Previous owner (1 month ago) changed the left rear brake cylinder. Pedal felt spongy when I bought the truck, so I bled the right rear, then the left rear brake cylinders. I'm 99.99% positive that I had no air left in those cylinders, and the master cylinder was kept topped-off the whole time. However, now the BRAKE light comes on whenever I press the brake pedal. What did I do wrong, or is there something else I should look at?

Good call, xsvector! The right rear cylinder had a 1/8-inch hole in the forward boot, and there was brake fluid all over the inside of the drum, and all over both shoes. Luckily, the previous owner had told me he bought a second new cylinder but hadn't installed it yet (it was still in the wrapper under the seat). I cleaned up the drum and brake components, then replaced the wheel cylinder and bled the rear brakes again. However, I still have the BRAKE light coming on, and the pedal still goes to the floor and feels really mushy. I'm going to recheck the rear cylinders for air again tonight, and if they're okay, I'll try bleeding the front wheels. If that doesn't resolve the problem, since I don't appear to have any leaking brake fluid anywhere, I'll probably try the master cylinder and/or the proportioning valve next. Good call, xsvector! The right rear cylinder had a 1/8-inch hole in the forward boot, and there was brake fluid all over the inside of the drum, and all over both shoes. Luckily, the previous owner had told me he bought a second new cylinder but hadn't installed it yet (it was still in the wrapper under the seat). I cleaned up the drum and brake components, then replaced the wheel cylinder and bled the rear brakes again. However, I still have the BRAKE light coming on, and the pedal still goes to the floor and feels really mushy. I'm going to recheck the rear cylinders for air again tonight, and if they're okay, I'll try bleeding the front wheels. If that doesn't resolve the problem, since I don't appear to have any leaking brake fluid anywhere, I'll probably try the master cylinder and/or the proportioning valve next.

Follow-up: After replacing the RR wheel cylinder, I replaced the master cylinder with a reman unit. However, I still had the same soft-pedal problem. I still could find no leaks. Reluctantly, I took it into the shop. They found broken brake springs in the LR wheel and replaced them at no charge. Both rear drums and brake shoes were "saturated with brake fluid", so they replaced those (NOT at no charge). They recommended replacing master cylinder again with a brand-new (not reman) unit. At this point, they thought they had the problem licked, and told me I could pick up the truck that evening (second day) but when they road-tested the truck the brakes faded out on them again. They couldn't find any leaks either. Finally (evening of the third day, working 3+ hours past closing time) they replaced the ABS modulator and dump valve. They bled the entire system one more time, and now (four days and $1000+ later) I have good pedal and stopping performance. My wife says that, after this expense, further restoration efforts will have to be delayed for a while, but at least now my truck stops on a dime instead of a dollar! Follow-up: After replacing the RR wheel cylinder, I replaced the master cylinder with a reman unit. However, I still had the same soft-pedal problem. I still could find no leaks. Reluctantly, I took it into the shop. They found broken brake springs in the LR wheel and replaced them at no charge. Both rear drums and brake shoes were "saturated with brake fluid", so they replaced those (NOT at no charge). They recommended replacing master cylinder again with a brand-new (not reman) unit. At this point, they thought they had the problem licked, and told me I could pick up the truck that evening (second day) but when they road-tested the truck the brakes faded out on them again. They couldn't find any leaks either. Finally (evening of the third day, working 3+ hours past closing time) they replaced the ABS modulator and dump valve. They bled the entire system one more time, and now (four days and $1000+ later) I have good pedal and stopping performance. My wife says that, after this expense, further restoration efforts will have to be delayed for a while, but at least now my truck stops on a dime instead of a dollar!

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If the master cylinder is replaced, care must be taken to prime the new master cylinder by removing all of the air and completely filling it with brake fluid. The spongy feeling is air that is still in the circuits. You will need to bleed the back brakes as well as the front ones again. The order that you bled them seems correct, but perhaps there remained some air in the main trunk lines.

For the best results 2 people are needed. Start at the further distance wheel cylinder and bleed at least three (3) master cylinder reservoir volumes of fluid (back brakes). Bleed the fluid with use of a piece of tubing attached to the bleed port that is long enough to reach almost to the bottom of a long neck or tall clear jar (clear drink bottle works well). When the bleeding begins, after one or two brake pedal pushes, make sure that the end of the tubing is below the surface of the fluid and keep it under. It best to have a clear bleed line (to observe air). Keep pumping the brake pedal while being careful to not completely empty the master cylinder reservoir (leave 1/4 full always). Repeat the same technique for each wheel cylinder with at least two (2) reservoirs full for front brakes. Partially close the bleed ports when almost finished (at least 5 pedal strokes without exit of any air). Completely close the ports during the down stroke of the brake pedal, with the tubing still attached. Be sure each bleed port is closed snuggly.
Most of the brake fluid can be reused, but not the darker portion at the bottom of the jar.

Did you also bleed the rear brakes? Also try the gravity bleed method working from the right rear wheel, then left rear, right front, then left front. Be SURE to keep the master cylinder full at all times while bleeding.

So long as the brake booster is working, test it by turning on the engine, press the brake pedal all the way down, then shut off engine keeping your foot on the brake pedal, if the pedal comes up slightly pushing against your foot then the booster IS working.

Did you adjust the rear shoes out? If the rear drum brakes are out of adjustment they will give you a lot of pedal travel. If the pads are worn have no fear of that U-CLIP brake spring, just change one shoe at a time. Take the spring off one side, change the shoe, put the spring back on the post and do the same to the other shoe, no problem.

I just went to Brake Masters this morning and had them replace the Master Cylinder since I was experiencing the pedal very spongy and going to the floor. When they replaced the Master Cylinder and they gave me back the car, the brakes were still spongy and going to the floor. I addressed this to them and they took another look at it, but when I took it for a second time, the brakes were extremely spongy. It was almost like they gave me back my car in worst condition to when I brought it in. Can you help?